Continuous flow, rotary dynamic blood pumps are of significant medical interest. Some successes have been achieved, but the majority of these designs are physically large, electromagnetically complex, and consume significant amounts of power. An innovative prototype blood pump incorporating a single active axis magnetic bearing is proposed. key design features include a passive radial bearing, and a pull-pull axial thrust bearing. A nonlinear axial controller will be designed, to implement a "virtually zero power" system, without incorporating bias magnets. The axial bearing can function in cooperation with ferromagnetic material in the impeller blades, eliminating the need for an impeller shroud. Velocity, rather than displacement, control of the rotor position will be used, to further enhance a virtually zero power bearing operation. Hydraulically, the design incorporates simple, effective impellers, and large, low-shear passages that allow good wash flow. In Phase I, a magnetic bearing system will be designed, built, and tested with a pump fabricated using stereolithography technology. A special, ironless motor will minimize motor-induced magnetic loads. The electronic controller will be breadboarded. This system will be performance tested in blood analog solution, in all orientations. During Phase II, an implantable prototype will be designed, built, and extensively bench and in-vivo tested, preparatory to Phase III qualification. PROPOSED COMMERCIAL APPLICATIONS: Heart disease remains the leading cause of death and disability within the United States. Of the 200,000 Americans who die each year due to heart- related problems, about 30,000 to 60,000 could probably be saved with heart transplants. However, the shortage of donor hearts precludes this, and has stimulated the development of many mechanical heart assist and replacement devices. Should mechanical assist pumps prove sufficiently safe and reliable, the potential use to improve the quality of life for cardiac-impaired patients dramatically expands the market.